Fluorinated alkyl silanes and their use



United States Patent 3,012,006 FLUORINATED ALKYL SILANES AND THEIR USE George W. Holbrook and Omar W. Steward, Midland, Mich, assignors to Dow Corning Corporation, Midland, Mich., a corporation of Michigan No Drawing. Filed Apr. 24, 1958, Ser. No. 730,540 11 Claims. (Cl. 260-465) This invention relates to fiuorinated alkyl silanes and their use as oil repelling agents.

The water repelling characteristic of organosiloxanes is well known, and these materials are used extensively to render such materials as ceramics, masonry and fibrous materials water repellent. However, the oil repellency of the heretofore employed hydrocarbon substituted siloxanes is not as good as may be desired. That is, although siloxane coated materials are oil resistant, the oil will not stand up on the treated surfaces in droplets as water does. Consequently, it has long been desired to produce siloxanes which have the capacity to render surfaces oil repellent without deleteriously affecting the other desirable properties of siloxanes such as water repellency and hand.

It is the object of this invention to provide novel compositions of matter which are useful as coating compositions. Another object is to provide oil and water repellent articles of manufacture. Other objects and advantages will be apparent from the following description.

This invention relates to a composition of matter comprising a siloxane containing at least 48% by weight fluorine, consisting essentially of siloxane units of the formula in which n is an integer from 2 to 18 inclusive, R is a divalent aliphatic hydrocarbon radical, m is 0 or 1, Y is a divalent aliphatic radical containing a functional linkage of the group ester, ether, amine and amide, there being a total of less than 18 atoms, exclusive of hydrogen, in Y and R.

The above siloxane compositions are best prepared by hydrolyzing silanes of the formula in which n, R, Y and m are as above defined, and X is of the group hydrogen atoms, halogen atoms, monovalent hydrocarbonoxy radicals and monovalent halohydrocarbonoxy radicals. The hydrolysis of the silane can be carried out in the conventional manner for hydrolyzing SiH containing silanes. This hydrolysis is best carried out under acid conditions.

The silanes of this invention are best prepared by reacting an olefin containing the above perfluoro group with a silane of the formula HSiX at an elevated temperature. If desired, the addition can be carried out in the presence of an addition catalyst such as platinum, platinum salts or peroxides. The reaction may be represented schematically by the equation In order to simplify the following detailed descriptions of the method of preparing the silanes of this invention various terms and symbols will be employed as follows. Z represents the perfiuoro group C F R represents an aliphatic olcfinic radical which when added to the silane becomes the divalent aliphatic radical R. The term divalent aliphatic radical containing a functional linkage represented by Y includes three variations. The first is that in which Y is composed entirely of a functional linkage such as the ester linkage,

' and are commercially available.

"ice

H --CHzN- and the third is that in which Y consists of one or more hydrocarbon portions and/or more than one functional linkage such as In those cases where there is no functional linkage in the silane, that is where m is 0, the silanes of this invention are prepared by reacting olefins of the formula ZR with silanes of the formula HSiX to give Z-RSiX in the manner described above. The remaining silanes of this invention are best prepared by reacting functional ole-fins of the formula ZYR with silanes of the formula HSiX to give ZYRSiX The starting perfiuoro olefins ZR can be prepared from the corresponding perfiuoro acids of the formula ZCOOH. These perfluoro acids are known materials The preparation of the olefin from such acids involves the following steps. The acid ZCOOH is reacted with ethyl alcohol in the presence of sulfuric acid to give the ethyl ester ZCOOEt. This ester is then reacted to about 0 C. with a mixture of methyl magnesium bromide and isopropyl magnesium bromide to give the secondary alcohol ZCHOHCH The ratio of reactants employed is one mol ester, one mol methyl magnesium bromide and 1.25 to 1.5 mols of isopropyl magnesium bromide. This secondary alcohol is then dehydrated by heating to 200 to 300 C. in the presence of P 0 to give an olefin of the formula ZCH=CH The starting olefins of the formula ZY R are prepared by reacting aliphatic unsaturated organofunctional compounds with perfiuoro functional compounds of the formula ZB where B represents an organic functional group such as carboxyl, sulfonic acid, acyl chloride, alcohol and the like. The reaction of the unsaturated functional compound with the functional perfluoro compound produces unsaturated ethers, esters, amides and amines which are employed to make the silanes of this invention. Typical examples of the preparation of these ZYR' compounds are shown below.

Ester H S O 4 so 0 OH-l-allyl alcohol zo o o CHiCH=CH2 Amide Z SO2F+a1lyl amine- ZSO2NHOHzCH=OH,

Ether 20 0: Z CEg0H+allyl chloride- Z CH Q C HZCH=CH1 Amine The above starting olefins can be added to starting silanes having from one to four hydrogens attached to the silicon. For example, the starting silane can be HSiCl H SiCl H SiCl or SiH The most desirable starting silanes are those of the formula H SiX in which X is halogen or hydrocarbonoxy, that is -OR" where R" is a monovalent hydrocarbon or halogenated monovalent hydrocarbon. When the addition of the olefins to this type of silane is carried out employing an excess of silane good yields of the mono addition product are obtained to give the silanes containing one hydrogen on the silicon. These products can then be hydrolyzed directly to the siloxanes of this invention by conventional methods. I

acid to give a silane of the formula H ZYaRSHOR"):

The latter is then hydrolyzed in the conventional manner for hydrolyzing hydrocarbonoxy silanes to give the siloxanes of this invention. The hydrolysis is best carried out under acid conditions.

.In the siloxanes and silanes of this invention the perfiuoro group Z can be any perfiuoro aliphatic group containing from- 2 to 18; carbon atoms such as pentafiuoroethyl, heptafiuoropropyl, nonafluorobutyl and C13F37. It should be understood that these perfluoro groups can bev eitherlinear or. branched in structure. Thus, for example, the perfluoro group Z can be of the type 'Y can be any divalent aliphatic radical containing at least one functional group of the type ester, ether, amine and amide. Spccificexamples of ester functional linkages are those derived from carboxylic acids and sulfonic acids or their equivalents, the corresponding acylhalides or acid anhydrides. those derived from either primary or secondary amines and carboxylic acids or sulfonic acids Specific examples of Y groups which are within the scope of this invention are In ;the compositions of this invention R can beany divalent aliphatic hydrocarbon radical of less than 18 carbon atoms. Specific examples of R are saturated radicals such as ethylene, propylenaundecylene and unsaturated aliphatic divalent hydrocarbon radicals such as vinylene and (CH CH=CH(CH The compounds in which R is an unsaturated radical can be prepared by adding any of theabove perfluoro compounds containing,- either two olefinic linkages or one or more acetylenic linkage. For example, one may react a compound of the formula ZCECH with the silane to give ZCH=CHSia One also may add a diolefinic derivative such as ZYCH CH=CHCH CH=CH to the silane to produce Compounds of'the type ZCECH can be prepared by adding HBr to ZCH=CH to give ZCH CH Br which is then brominated by heating in the presence of ultraviolet light to give ZCH CHBr which is dehydrohalogenated by heating in the presence of alcoholic KOH to give ZCECH.

In'the'silanes of this invention the X groups can be hydrogen or any halogen atom such as fluorine, chlorine, bromineor iodine, or any hydrocarbonoxy radical of the formula OR" in'which R" is any rnonovalent hydrocarbonradical such as methyl, ethyl, propyl, octadecyl, vinyl, allyl; hexenyl, cyclohexyl, cyclopentyl, cyclohexenyl,

pheny,.tolyl, xylyl, benzyl or xenyl; or any haogenatedv rnonovalent hydrocabon radical such as chloropropyl,

Specific examples of amide linkages are chloromethyl, bromophenyl, fluorotolyl or chlorocyclohexyl. Preferably the 0R groups are alkoxy groups of less than 10 carbon atoms such as methoxy, 2-ethylhexoxy, ethoxy or isopropoxy.

The siloxanes of this invention are particularly useful as a coating agent for base members in order to render them both oil and water repellent. In order for the composition to function successfully as an oil repellent coating the percent by weight fluorine in the siloxane should be at least 48%. The compositions can be applied to the base member in any suitable fashion such as by dipping, spraying or brushing. They also may be applied to the base member as such or in the form of solutions or aqueous emulsions.

In order to facilitate the curing of the siloxane on the base member, it is desirable to employ a curing catalyst. Any catalyst which is normally employed for curing hydrogen containing siloxanes is operative herein. These catalysts are well known and include salts of carboxylic acids such as zinc oetoate and dibutyltindiacetate, alkanol amine titanates such as triethanol amine titanate, alkanol amine zirconates such as triethanol amine zirconate, water soluble zirconium. compounds such as zirconium acetate and zirconium oxychloride and zirconium or titanium esters of aliphatic alcohols.

The compositions of this invention can be employedv on any kind of base member such as those made from glass, ceramics, metal, wood, or fibrous materials such as leather, paper and textiles made from wool, cotton, nylon, cellulose acetate, Dacron and the like.

After the siloxane has been applied to the base memher it is desirable to cure the siloxane. This'maybe done by heating at an elevated temperature such as from to C. or higher or by aging at room temperature in those caseswhere the base member will not Withstand prolonged heating. It should be understood'that the siloxane may be applied to the base member per se or it may -be formed in situ on the base member by contacting the base member with the silanes of this invention. As iswell known, such silanes hydrolyze on the surface of the base member to produce the siloxanes.

The term consisting. essentially of as employed in the claims means that the siloxanes are essentially of the structure indicated. However, thisterm indludes within the scope of the claims copolymers of the defined siloxanes with minor amounts of hydrocarbon substituted siloxanes which are often employed in connection with SiH containing siloxanes in order to stabilize the products. Examples of such siloxanes are thetriorganosilyl substituted siloxanes such as trimethylsiloxane, phenyldimethylsiloxane, triethy-lsilox-ane and siloxanes of the type;

in which D is a hydrocarbon radical and: the sum of'a and b is equal to 3; The term also includes the presence of minor amounts of dionganosiloxanc, monoorganosiloxane or SiO units in the polymers. Inall events, however, the fiuorine content of such siloxane copolymers should total at least 48% by weight.

The following abbreviations are employed in this specification: Me for methyl, Et' for'ethyl and Ph for phenyl.

The followingexamples are illustrative only and should not be construed as limiting the invention which is properly delineated'in the appended claims.

Example 1 A mixture of 249 'g. of l,l-dihydroperfluoroootanol, 112 g. of allyl bromide and 171 g. of anhydrous potassium carbonate was mixed with 300 ml. of acetone and refluxed for 3 /2 days. The reaction mixture Was-filtered to remove salts and the acetone was removed by distillation. 100 ml. of benzene were added to the residue and the solution was washed with water and dried by azeotropic distillation. The product was then fractionated to obtain allyl-l,l-dihydroperfluorooctylether, boiling point 177.8 to 178.1 C. at 745 mm., 21 1.3202, 11 1.561.

A mixture of 94.7 g. of the allyl-1,1-dihydroperfluorooctylether and .3 ml. of a solution of chloroplatinic acid in dimethylcarbitol containing .00122 g. of Pt per ml, was heated to 90 C. while 33.9 g. of trichlorosilaue was slowly added. After all the trichlorosilane was added the mixture was refluxed for 8 hours. The resulting product was distilled to give 3-(1;1-dihydroperfluorooctoxy)- propyltrichlorosilane, boiling point 125 C. at 7.5 mm., n 1.3613, 11 1.609.

73.2 g. of 3-(1,1-dihydroperfluorooctoxy)propyltrichlorosilane were dissolved in 100 ml. of anhydrous ether and then added to 9.5 g. of lithium aluminum hydride dissolved in 200 ml. of anhydrous ether. The mixture was allowed to stir overnight. Trimethylchlorosilane was added to destroy the excess lithium aluminum hydride. After stirring for 4 hours the reaction mixture was poured onto cracked ice. The ether layer was removed and dried over calcium sulfate and the product was then distilled to give 3-(1,1-dihydroperfluorooctoxy)propylsilane [C F CH O(CH SiH boiling point 83 C. at 9 mm., 21 1.3350 and d 1.458. a

8.5 -g. of absolute ethanol were added to a mixture of 43.8 g. of 3-(1,l-dihydroperfluorooctoxy)propylsilane, .3 ml. of a solution of chloroplatinic acid in dimethylcarbitol which solution contained .00122 g. of Pt per ml., and 100 ml. of anhydrous ether. stirred overnight and distilled to give 3-(1,1-dihydroperfluorooctoxy)propyldiethoxysilane n [clriaenlo cnnasuonon boiling point 115 to 116 C at 4 mm., n 1.3493, (1 1.338.

and having 21 1.3507 and d 1.631.

2 g. of this siloxane and .3 g. of a mixture of a toluene solution of zinc octoate and dibutyltindiacetate, which solution contained 9.35% by weight zinc and 3.28% by weight tin, were dissolved in ether to give 100 g. of solution. Wool fabric was dipped into this solution, air dried and then heated 15 minutes at 125 C. The fabric was then allowed to stand at room temperature. The pickup was 2% by weight silicone.

The oil repellency of the fabric was tested by measuring the time required for a drop of commercial lubricating oil to soak into the fabric. This test was made periodically after the sample had aged at room temperature for the times shown below.

The reaction mixture was In all cases the wool samples showed excellent water repellency.

Example 2 A mixture of 297 1g. of C F CH=CH and 60 g. of dichlorosilane was heated in an autoclave at 250 C. for 6 hours. The resulting product was distilled to give the silane boiling point 99 C. at 10 mm.

This chlorosilane was dissolved in diethylether and added dropwise to a large excess of water at 15 to 2 0 C. The siloxane layer was separated from the water, washed neutral and dried. The product was stripped to give a fluid polysiloxane having the unit formula H 'IFiaOHgCHgSlO This polysiloxane was dissolved in ether along with the siloxane catalysts of Example 1 and applied to wool. The pickup was 2%. The wool fabric was heated 15 minutes at 120 C. The oil repellency of the cured sample was then determined as shown in Example 1. The sample was then dry cleaned twice and the oil repellency after each dry cleaning was determined in the same manner. The fabric was allowed to stand for 31 days and it was again dry cleaned and the oil repeilency determined. Finally the oil repellency was again determined after 638 days. The results are shown in the table below. The treated wool showed excellent water repellency.

Time aging in days at room 0 temperature Time in minutes for il to soak in Dry cleaned Blank 1.

11. 25. 31 150. 638 1 week.

Excellent oil and water repellency was also shown when this siloxane was applied to cotton fabric.

Example 3 boiling point 143 C. at 740 mm.

47 g. of this silane were mixed with 4.5 g. of lithium aluminum hydride in anhydrous diethylether at 0 C. The mixture was stirred for 1 hour and the excess lithium aluminum hydride was decomposed with ethanol. The ether solution was washed with cold water and dried over calcium sulfate. The product was distilled to give 2- (heptafiuoropropyl)ethylsilane (C F 'CH CH SiH boiling at 72 C. at atmospheric pressure and having a refractive index at 25 C. of 1.3145.

7.1 g. of absolute ethanol were added to a solution of 17.1 g. of 2-(heptaflu0ropropyl)ethylsilane and 5 drops of a dimethylcarbitol solution of chloroplatinic acid containing .00122 g. of Pt per ml., in ml. of ether. The mixture was stirred overnight and distilled to give the silane Z-(heptafluoropropyl)ethyldiethoxysilane boiling 83 C. at 52 mm. and having n 1.3445.

This silane was then hydrolyzed by adding it to 1 N hydrochloric acid. The hydrolyzate mixture was ex' there wasobtained a fluid polysiloxane having the unit formula H Cnnornontsio This siloxane was applied to wool fabric in a manner in which n is an integer from 2 to- 18 inclusive, Y is a divalent aliphatic radical containing a functional linkage of the group consisting of ester, ether, amine and amide linkages, said Y group being linked to both a carbon of V 5 the R group and a carbon of the C F group, m'is a identigal with the sliloxane 01? Example 1. The resulting number of the group consisting of and 1 and R is a F e n a v i that? Wool Sana) e owe to'age divalent aliphatic hydrocarbon radical, there be ng a perature for the time indicatedbelow. Theoil repellency total of less than 18 atoms exclusive of hydmgen in g z t i i Y and R and (2) thereafter curing the silox-ane'coating.

1 1 an i w i Own m Xamp e 2. A method comprising (1), applying to a base memis are gwm m e a e e ber selected from the group consisting of ceramic,vmetal and organic fibrous materials a coating of polysiloxane Timein a Time aging in daysat room temperature minultgs for of umt formula 01 o H. Soak 111 c nFEM-IC HICHZ lO Blank 1, in which n is an integer from 2 to 18 inclusive which h polysiloxane contains at least 48 percent by weight fluoli" 'I s. rine and (2) thereafter curing the siloxane coating.

Z; 20 3. An article of manufacture prepared in accordance a9 3: with claim 1. 32 4. An article of manufacture prepared in accordance with claim 2. mmeml 5; A composition of matter comprising a silane ofthe These samples showed excellent water repellency. 25 formula 1 a H Er mple 4 cnFrim Rs xi Good oil repellency is obtained when the siloxane of I Example 1 is applied in accordance with the method of which 1S E8 1013 lnclllslve, 1S a that example to the following base members: glass, divalent ahphaflc f f colltalmng a fullFtloIlal 11I1kge leather, paper, wood and to textiles of linen, nylon, the groupwnslstmg ether; 31111118, and amid? polyester fibers of terephthalic acid and ethylene glycol, lmkages, Said group bemglmked to both a carboll polyacrylonitrile fibers and cellulose acetate fibers. 1 R l fl carbcl'lofihe n zn-t-l group, 15 a fly lp 5 divalent aliphatic hydrocarbon radical, there being a hump total of less than 18 atoms, exclusive of hydrogen, in Y When the. following fluoroolefins are added to the 0 and R, and X is selected from the group consisting of silence shown by heating a mixture of the two in the hydrogen atoms, halogen atoms; monovalent hydropresence of chloroplatinic acid as shown in Example 1 carbonoxy radicals and monovalent halohydrocarbonoxy and the resulting silane' is converted to a siloxane as radicals there being sutficient carbon-bonded. fluorine in shown in Examples 1 or 2, fluid siloXanes-of the follow- 40, said silane that the corresponding siloxane contains at ing unit formulae are obtained. least 48 percentby weight carbonebonded fluorine.

Olefin Silane Silane addition product Unit formulae of 'siloxane V H H c rwczon HRSlClZ C3F7CH=CHSlCl2 C;F1CH=CHSiO.

, H C7F 5COOCH2CH=CHn SiH; G7Fi5COO(OHs)3SiH C7F15COO(CHz)zSiO.

H C7F15SOQOCHZCH=CHQ Sl L C7F15S02O(CH2)1SlBra C7F15SOz0(CH2)sSiO. n H O7FHSVO2NHCHQOHZCHZ HzSiF: -e C1F15SO2NH(CH2)3SiF2 C7FiaSO:NH(CH2)sSi0.

H C7F| CONHCHzCH=CHz HSiC1(OC4HsCl)2-.. O7F15CONI'I(CH2)3S1C1(OC4HsC1)z 07F\5CONII(CH2)SSiO.

H H' C3F 7CHzCHgNHCHsCH=CH: HzSlClz CsF 7OH2CH2NH(CHz)sSiC12 CsFnCHzCHgNH CHfisSlCL H H C sF; CHgOOC(CH2)xOH=CHz HzSiCla CISFB7CH2OOC CH2110S1012 .O18 37OH2OOC(CH2)lUSlO- Me Me H Me H OgF17CHz0CHCH:OCH2OH=CHz HzSiClz CsFuOH OCHGH O(OHQgSiOl; CgF GHqOGHCHgO(CHzhSiO.

Me Me H Me H CsF CONHCH2CH2NCH2CH=CH2 HzSiCl: GsFnCONHCHzCHgN(CH2)3SiClg r 013F170ONHCH2CH2N(CH2)3slO.

6. A composition of claim 5 in which X is an alkoxy radical of less than 10 carbon atoms.

7. As a composition of matter a siloxane containing, at

least 48% by weight fluorine and consistingpessentially of' siloxane units of the formula H CnF2 +1YRSi0 inwhich n is an integer from'2'to l8-inclusive, Y is a divalent aliphatic radicalcontaining a-functional linkageof the group consisting of ester, ether, amine'and amide linkages, said Y group being linked to both a carbon of the R group and a carbon of the Q 1 group and R is a divalent aliphatic hydrocarbon radical, there being a total of less than 18 atoms, exclusive of hydrogen, in Y and R.

8. A polysiloxane of the unit formula in which n is an integer from 2 to 18 inclusive and Y is a divalent aliphatic radical containing a functional linkage selected from the group consisting of ester, ether, amine and amide linkages, said Y groups being linked to both a carbon of the CH CH CH group and carbon of the C F +1 group said siloxane containing at least 48 percent by Weight fluorine.

9. A method comprising (1) applying to a base member selected from the group consisting of ceramic, metal and organic fibrous materials a coating of polysiloxane of the formula H CnFznflYCl'i'zCHaCHgsiO in which n is an integer from 2 to 18 inclusive and Y is a divalent aliphatic radical containing a functional linkage selected from the group consisting of ester, ether, amine and amide linkages, said Y group being linked to both 1% a carbon of the -CH CH H;- group and carbon of the C F group and thereafter curing the polysiloxane. 10. An article of manufacture prepared in accordance with claim 9.

11. As a composition of matter 11 CrFrsGHzCEzSlC-lg References Cited in the file of this patent OTHER REFERENCES McBee et al.: Iour. of the American Chem. Society, vol. 79, May 1957, pp. 2329-2332.

Clark, R. T.: Elastomeric Fluoroalkyl Siloxane Copolymers, WADC Technical Report 54-213, July 1957, pp. III and 18 relied on. 

1. THE METHOD COMPRISING (1) APPLYING TO A BASE MEMBER SELECTED FROM THE GROUP CONSISTING OF CERAMIC, METAL AND ORGANIC FIBROUS MATERIALS A COATING OF SILOXANE CONTAINING AT LEAST 48% BY WEIGHT FLUORINE AND CONSISTING ESSENTIALLY OF SILOXANE UNITS OF THE FORMULA 